mpload: command not found

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH
/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin

If it's empty, You may set the PATH variable with this command

export PATH="/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin"

On Debian possible default full paths are:

/usr/bin/mpload - from package: mpdtoys

You may install the required package with command apt-get install {package}

Error in other languages:
mpload: bevel nie gevind nie
mpload: comandă negăsită
mpload: comando não encontrado
mpload: commande introuvable
mpload: command not found
mpload: käsku ei ole
mpload: không tìm thấy lệnh
mpload: komanda nerasta
mpload: Kommando nicht gefunden.
mpload: kommandot finns inte
mpload: komut yok
mpload: nie znaleziono polecenia
mpload: níor aimsíodh an t-ordú
mpload: no se encontró la orden
mpload: no s'ha trobat l'ordre
mpload: opdracht niet gevonden
mpload: parancs nem található
mpload: perintah tidak ditemukan
mpload: príkaz nenájdený
mpload: příkaz nenalezen
mpload: команда не найдена
mpload: командата не е открита
mpload: 命令找不到
mpload: コマンドが見つかりません